1. Field of the Invention
This invention relates to a lubricant for an image forming apparatus and more specifically for an image carrier assembled into an image forming apparatus.
2. Description of the Related Art
In general, image forming apparatus such as a copying machine, which uses the electrostatic copying process or an electrophotographic process, includes an image reading section for illuminating a document with light and leading the reflected light to an image carrier, an image forming section having the image carrier on which electrostatic latent images are formed by the reflected light emitted from the image reading section and then images on the document are reproduced, and a material delivering section for supplying material such as plain paper sheets or O.H.P. sheets to the image forming section and for taking out the material on which the images reproduced by the image forming section are transferred.
The image reading section has a document table on which a document is mounted, an illuminating device for illuminating the document and an optical unit for guiding the reflected light from the document.
The image forming section includes an image carrier or a photoconductor for successively forming electrostatic latent images corresponding to the reflected light coming from the reading section, a charging device for supplying electric charges having required polarities to the photoconductor, a developing device for supplying developing agents or toner to the electrostatic latent images to visualize the images, a transferring unit for transferring the developed images to a paper sheet, a fixing unit for melting the toner and fixing them to the paper sheet, and a cleaning unit having an elastic blade and pressed on the outer peripheral surface of the photoconductor under a prescribed pressure and an eraser device, for returning the electric charge distribution to the initial state and for removing the images as well as the toner thereon left on the surface of the photoconductor.
The material delivering section has paper cassettes for supplying paper sheets on which images are to be transferred, a paper feeder for feeding the paper sheets to the image forming section, and an output unit for delivering the image-transferred paper sheets outside of the copying machine.
When the copying machine is first used after it has been manufactured, the cleaning unit is generally processed by means of so-called setting-up process which is intended to reduce friction between the elastic blade and the photoconductor by coating them with a solid lubricant such as vinylidene trifluoride.
The reduction of the friction between the photoconductor and the blade by the use of the lubricant can prevent the breakage of the blade.
The published unexamine Japanese Patent Application 57-144542 which was filed on Sep. 7, 1982 discloses a solid lubricant of this kind.
When, however, the friction between the blade and the photoconductor is large, the use of the lubricant disclosed in mention above patent application cannot always prevent the blade from being broken. The use of a lot of lubricant allows the lubricant to be mixed with the developer for developing the latent images so that the developing characteristics such as the condensation of the developer are apt to be changed during a long period of time.
Further, a lot of lubricant mixed with the developer likely damages the surface of the photoconductor.